Birch bark is a low-value waste product in the forest industry today. Ekman, R., Holzforschung, (1983) 37, 205. Approximately 230,000 tons of birch bark are generated per year. For example, a single paper mill can generate 70 tons of birch bark per day. Thus, vast quantities of birch bark and its chemical components are available.
Birch bark is a potential source of a variety of organic chemicals. Several triterpenoids have been identified in birch bark extracts. For example, lupeol, betulin, betulinic aldehyde, betulinic acid, methyl betulinate, lupenone, betulonic aldehyde, betulonic acid, xcex2-amyrin, erythrodiol, oleanolic aldehyde, oleanolic acid, methyl leanolate and acetyl oleanolic acid are all present in the outer bark of Betula verrucosa. Eckerman, C.; (1985) Paperi ja Puu, No. 3, 100. In addition, several suberinic acids isolated from birch bark, as well as several triterpenoids, have been identified in the bark of Betula verrucosa. Ekman, R., Holzforschung, (1983) 37, 205.
The chemical constituents of birch bark are useful in pharmaceutical and industrial applications. For example, U.S. Pat. No. 5,750,578 discloses that betulin possesses antiviral properties and is useful to treat herpesvirus. Betulin also possesses antifeedant activity against boll weevils, and anti-inflammatory activity (Miles, D. H., 1994, J. Agric. Food. Chem., 42, 1561-1562 and Recio, M., Planta Med., 1995, 61, 9-12. In addition, betulin showed cough suppressant and expectorant effects. Jinuhua, W., Zhongguo Yaoxue Zazhi, (1994), 29(5), 268-71. Betulin is also a useful starting material for preparing alobetulin and derivatives thereof, which posses useful pharmacological properties.
Betulin can be converted to betulinic acid, which is useful as a therapeutic agent. For example, Pisha, E. et al., (1995) J. M. Nature Medicine, 1, 1046-1051 discloses that betulinic acid has antitumor activity against human melanoma, e.g., MEL-1, MEL-2 and MEL-4. In addition, Fujioka, T. et al., J. Nat. Prod., (1994) 57, 243-247 discloses that betulinic acid has anti-HIV activity in H9 lymphocytic cells.
Ambrettolide (cis-hexadec-7-enolide), a naturally occurring compound, is used to induce musk fragrance in perfumes. Ambrettolide is found in the vegetable oil of ambrette seeds. The synthesis of ambrettolide is accomplished from 9,10,18-trihydroxyoctadecanoic acid via a high-yielding multi-step synthesis. Seoane, E., J. Chem. Soc. Perkin Trans. (1982), 1837-1839. Therefore, 9,10,18-trihydroxyoctadecanoic acid, which is present in birch bark, is a useful precursor for the synthesis of ambrettolide.
9,10-Epoxy-18-hydroxyoctadecanoic acid is also present in birch bark. 9,10-Epoxy-18-hydroxyoctadecanoic acid is an environmentally-friendly spoilage deterrent and a rot-resistant additive for wood composites. Sweitzer, P., et al., Induction of Resistance in Barley Against Erysiphe graminis by Free Cutin Monomers, Physiol. Mol. Plant Pathol, (1996) 49(2) 103-120.
Suberin is another major component of birch bark. Suberin is an insoluble polymeric material that is attached to the cell walls of periderms. Kola, P. E. et al., Ann. Rev. Plant. Physiol., (1981), 32: 539-67. Suberin is generally an ester of fatty acids and polyphenolic polymers. Suberin of birch bark is typically a biopolyester of primary hydroxy, epoxy and dicarboxylic acids. Ekman, Holzforschung, (1983) 37, 205-211.
Suberin possesses several industrial applications. See, e.g., Taylor and Francis, Forests Products Biotechnology, A. Bruce and J. W. Palfreyman (editors), 167, 179-181 (1998); Peter E. Laks and Peggy A. McKaig, Flavonoid Biocides: Wood Preservatives Based on Condensed Tannins, Horzforschung, 42, 299-306 (1988); Etherington and Roberts, Dictionaryxe2x80x94birch(bark), http://sul-server-2. stanford.edu/don/dt/dt0328. html, 1, Jun. 23, 1999; P. E. Kolattukudy, Structure, Biosynthesis, and Biodegradation of Cutin and Suberin, Ann. Rev. Plant Physiol., 32, 539-67 (1981); and N. Cordeiro, M. N. Belgasem, A. J. D. Silvestre, C. Pascol Neto, A. Gandini, Cork Suberin as a new source of chemicals, Int. Journal of Biological Materials, 22, 71080 (1998). Suberin is useful as a dispersant in many industrial applications (e.g., carbon black slurries, clay products, dyes, cement, oil drilling muds, and asphalt emulsifiers). Suberin is also useful in binders for animal pellets, conditioners for boiling water, anti-oxidants and additives to lead-storage battery plate expanders. McGraw-Hill Concise Encyclopedia of Science and Technology, Fourth Edition, 1998.
Polyphenolic polymers are also present in birch bark as a constituent of suberin. Polyphenolic polymers may be classified as soluble polyphenolic polymers or non-soluble polyphenolic polymers. Soluble polyphenolic polymers are the portion of polymers which are soluble in water under both acidic and basic conditions. The non-soluble polyphenolic polymers are non-soluble in water at a pH below about 4.0, but soluble in acetone, alcohols and other polar solvents. The non-soluble polyphenolic polymers may have a different formulation from the soluble polyphenolic polymers. However, the non-soluble polyphenolic polymers may be used in the same industrial applications as the soluble polyphenolic polymers.
Polyphenolic polymers are non-toxic and biodegradable and may be formulated for numerous purposes (e.g., as anti-oxidant reagents, anti-fungal materials, coating materials, co-polymers, wood preservatives, tire cord adhesives, foundry cord binders, rigid and floral foams, ion exchange resins, industrial water purification flocculants, textile dyes, food additives and pharmaceuticals). Pizzi, Wood Bark Extracts as Adhesives and Preservatives, 167-181, Taylor and Frances, Forest Products Biotechnology, Bruce and Palfreyman (editors), 1998.
Suberin from betula verucosa contains at least 35 fatty acids which makes it hardly usable in industry. U.S. Pat. No. 4,732,708 issued to Ekman, R. et al. discloses a process for manufacturing suberinic acid. The process, however, does not attempt to separate the individual fatty acids. In addition, due to the crucial differences in the fundamental chemistry between the types of birch trees (i.e., the type and distribution of fatty acids), the procedures employed in U.S. Pat. No. 4,732,708 issued to Ekman, R. et al. may not be useful for the isolation of fatty acids from species of birch bark other than those employed in U.S. Pat. No. 4,732,708. As such, a method for isolating the individual fatty acids from the bark of other species of birch is needed.
The current methods employed to isolate not only betulin, but other components in birch bark (e.g., lupeol; betulinic acid; 9,10-epoxy-18-hydroxyoctadecanoic acid; 9,10,18-trihydroxyoctadecanoic acid; and polyphenolic polymers) are costly, inefficient or unsafe. A need therefore exists for safer, more cost-efficient methods to obtain commercial quantities (e.g., tons) of betulin; as well as commercial quantities (e.g., kg) of lupeol; betulinic acid; 9,10-epoxy-18-hydroxyoctadecanoic acid; 9,10,18-trihydroxyoctadecanoic acid; and polyphenolic polymers from birch bark. In addition, a need also exists for an industrial scale process for producing these products.
Different species of birch bark may include different natural products or may include the same natural products in differing amounts and differing ratios. A mixture of natural products (e.g., a mixture of suberinic acids) can be isolated from birch bark. Depending upon the particular species of birch bark and the specific methods and conditions employed to isolate the natural products, the ratios and amounts of natural products (e.g., suberinic acids) isolated can vary. As such, what is needed are methods and conditions that can be employed to isolate, from birch bark, a mixture of specific suberinic acids, in varying amounts and ratios. These mixtures of specific suberinic acids, in varying amounts and ratios can have different and distinct biological properties.
The present invention provides methods and conditions that can be employed to isolate, from birch bark, mixtures of specific suberinic acids, in varying amounts and ratios. The mixtures of suberinic acids can possess distinct and suitable biological properties, including for use in the cosmetic and skin care field. The present invention also provides methods to provide commercial quantities (e.g., tons) of these mixtures of suberinic acids.
The present invention also provides for a process for isolating, from outer birch bark, 9,10-epoxy-18-hydroxyoctadecanoic acid; 9,16-dihydroxyhexadecanoic acid; 9,10,18-trihydroxyoctadecanoic acid (phloionolic acid); 20-hydroxyeicasanoic acid; 22-hydroxydocosanoic acid; 18-hydroxyoctadec-9-enoic acid; docosandioic acid; octadec-9-enedioic acid; other carboxylic acids; betulin; and mixtures thereof, in varying amounts and ratios.
The present invention provides a process for isolating, from outer birch bark, at least one of 9,10-epoxy- 18-hydroxyoctadecanoic acid; 9,16-dihydroxyhexadecanoic acid; 9,10,18-trihydroxyoctadecanoic acid (phloionolic acid); 20-hydroxyeicasanoic acid; 22-hydroxydocosanoic acid; 18-hydroxyoctadec-9-enoic acid; docosandioic acid; and octadec-9-enedioic acid; comprising: (1) subjecting the outer birch bark to hydrolysis to provide a second outer birch bark and a second solution; (2) separating the second solution from the second outer birch bark; (3) condensing the second solution at a temperature below about 50xc2x0 C. to provide at least one of 9,10-epoxy-18-hydroxyoctadecanoic acid; 9,16-dihydroxyhexadecanoic acid; 9,10,18-trihydroxyoctadecanoic acid (phloionolic acid); 20-hydroxyeicasanoic acid; 22-hydroxydocosanoic acid; 18-hydroxyoctadec-9-enoic acid; docosandioic acid; and octadec-9-enedioic acid.
The present invention also provides a process for isolating non-soluble polyphenolic polymers and fatty acids from outer birch bark comprising: (1) subjecting the outer birch bark to hydrolysis in an aqueous alcohol solution to provide a second birch bark and a second solution; (2) separating the second solution from the second outer birch bark; (3) adding water to the second outer birch bark to provide a third solution and a third outer birch bark; (4) separating the third solution from the third outer birch bark; (5) acidifying the third solution to a pH of about 3.0 to about 4.0 to give a fourth solution and a mixture of non-soluble polyphenolic polymer and fatty acids; and (6) separating the mixture of fatty acids and non-soluble polyphenolic polymers from the fourth solution.
The present invention also provides a process for isolating fatty acids and soluble polyphenolic polymers from outer birch bark comprising: (1) subjecting the outer birch bark to hydrolysis in an aqueous alcohol solution to provide a second outer birch bark and a second solution; (2) separating the second solution from the second outer birch bark; (3) adding water to the second outer birch bark to provide a third outer birch bark and a third solution; (4) separating the third solution from the third outer birch bark; (5) acidifying the third solution to a pH of about 3.0-4.0 to give a fourth solution and a solid; (6) separating the solid from the fourth solution; (7) adding an alcohol to the fourth solution to provide a fifth solution and a precipitate; (8) separating the precipitate from the fifth solution; and (9) condensing the fifth solution to provide a mixture of fatty acids and soluble polyphenolic polymers.
The present invention also provides a composition comprising at least one of 9,10-epoxy-18-hydroxyoctadecanoic acid; 9,16-dihydroxyhexadecanoic acid; 9,10,18-trihydroxyoctadecanoic acid (phloionolic acid); 20-hydroxyeicasanoic acid; 22-hydroxydocosanoic acid; 18-hydroxyoctadec-9-enoic acid; docosandioic acid; and octadec-9-enedioic acid; wherein the composition is obtained from a process comprising: (1) subjecting outer birch bark to hydrolysis to provide a second outer birch bark and a second solution; (2) separating the second solution from the second outer birch bark; and (3) condensing the second solution at a temperature below about 50xc2x0 C. to provide at least one of 9,10-epoxy-18-hydroxyoctadecanoic acid; 9,16-dihydroxyhexadecanoic acid; 9,10,18-trihydroxyoctadecanoic acid (phloionolic acid); 20-hydroxyeicasanoic acid; 22-hydroxydocosanoic acid; 18-hydroxyoctadec-9-enoic acid; docosandioic acid; and octadec-9-enedioic acid.
Lupeol, betulinic acid and betulin can optionally be removed from the outer birch bark prior to the hydrolysis. The hydrolysis is carried out at a pH of greater than about 7.0, at a pH of less than about 7.0, or at a pH of about 6.5 to about 7.5.
When the hydrolysis is carried out at a pH of greater than about 7.0 and a mixture of 9,16-dihydroxyhexadecanoic acid; 9,10-epoxy-18-hydroxyoctadecanoic acid; 9,10,18-trihydroxyoctadecanoic acid (phloionolic acid); 20-hydroxyeicasanoic acid; 22-hydroxydocosanoic acid; 18-hydroxyoctadec-9-enoic acid; docosandioic acid; and octadec-9-enedioic acid is obtained in a ratio of about 1.0-3.0:20.0-30.0:1.0-3.0:1.0-3.0:12.0-16.0:3.0-5.0:25.0-35.0:3.0-6.0.
When the hydrolysis is carried out at a pH of than about 7.0 and a mixture of 9,16-dihydroxyhexadecanoic acid; 9,10-epoxy-18-hydroxyoctadecanoic acid; 9,10,18-trihydroxyoctadecanoic acid (phloionolic acid); 20-hydroxyeicasanoic acid; 22-hydroxydocosanoic acid; 18-hydroxyoctadec-9-enoic acid; docosandioic acid; and octadec-9-enedioic acid is obtained in a ratio of about 1.0-3.0:0-1.0:45.0-65.0:0.1-3.0:12.0-18.0:8.0-15.0:1.0-6.0:1.0-6.0.
When the hydrolysis is carried out at a pH of about 6.5 to about 7.5 and a mixture of 9,16-dihydroxyhexadecanoic acid; 9,10-epoxy-18-hydroxyoctadecanoic acid; 9,10,18-trihydroxyoctadecanoic acid (phloionolic acid); 20-hydroxyeicasanoic acid; 22-hydroxydocosanoic acid; 18-hydroxyoctadec-9-enoic acid; docosandioic acid; and octadec-9-enedioic acid is obtained in a ratio of about 1.0-3.0:0-1.0:45.0-75.0:1.0-6.0:10.0-18.0:1.0-5.0:4.0-16.0:1.0-6.0.
The birch can specifically be betula paperifera.